EMBRITTLEMENT OF ZIRCALOY-4 DUE TO HIGH TEMPERATURE HIDROGEN GAS

• Main Author: RYSWALDI (NIM : 12508005), RIDHO
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/23963
• Institution: Institut Teknologi Bandung

Zirconium is a grayish white metal that has the atomic number 40 and relative atomic mass of 91.224 g / mol. Properties owned strong zirconium, can be forged, and tenacious. Zirconium has a high hardness, neutron absorption cross section is very low and corrosion resistant. Zirconium alloys used in this study is Zircaloy-4. Zircaloy-4 is widely used as structural materials in nuclear reactors because this alloy has a low neutron absorption, corrosion resistance and good mechanical performance. However, the formation of the hydride susceptible Zircaloy-4 resulted in a significantly lower mechanical properties due to hydrogen embrittlement. The presence of hydride compounds cause the mechanical properties of Zircaloy-4 decreased. Series of observations made in this study to analyze the effect of hydrogen gas on Zircaloy-4. Hydrogen gas exposure performed at different temperatures variations. Temperature variation performed for 4 hours at a temperature of 400C, 500C, 600C, and 700C. After exposure to hydrogen gas, Zircaloy-4 then prepared unutuk observation. Observations were carried out to observe the microstructure, x-ray diffraction, and hardness test. The higher heat treatment temperature, the more hydrogen gas that goes. This is due to the increasing rate of diffusion of hydrogen heading into zirconium alloys. ZrH2 compounds formed in the alloy will be more and more. To determine the presence of compounds ZrH2 used XRD techniques. XRD technique was used to identify the crystalline phases in the material by determining the structure of the lattice parameters as well as to get the size partikel.Pada 4000C exposure to temperatures up to 7000C seen the emergence of a compound ZrH2 on difraktogram. Intensitas hydride compounds increased with increasing exposure temperature. Hardness obtained after exposure of hydrogen gas, at a temperature of hydrogen charging 400C temperature increases toward 500C, but then decreased at a temperature of 600C and 700C. Embrittlement in Zircaloy-4 is shown with reduced ductility but it does not mean an increase in strength as the general relationship between ductility and hardness.